Display cases are used in a number of different retail establishments for illustrating the products that are available for sale. In some instances these display cases may be refrigerated or non-refrigerated and may be placed in grocery stores, convenience stores, gas stations, restaurants, stadiums, race tracks, bakery, deli, hotels, or other retail establishments. It is desirable to place the products within a transparent housing, so that the customer can view them and hopefully make a purchase.
However, it has been discovered that exposure to light, or more generally electromagnetic radiation, both visible and invisible can cause a product to degrade. In some instances, the product may be an organic product where exposure to various wavelengths of radiation may cause the proteins or other components to break down. In other instances, the products may be inorganic but may contain materials (ex. plastics) which may degrade from exposure to various wavelengths of radiation. While it is desirable to offer the products in transparent cases, the exposure to radiation is undesirable as it will limit the shelf life of the product.